When a neo-Nazi assassinated Labour MP Jo Cox after she met constituents in Birstall, West Yorkshire last year, it was in the dying days of the bitter EU referendum campaign.

Remainers and Leavers downed megaphones, paid tribute, shed tears and vowed to be a little kinder to each other. When the campaign eventually resumed, a pall remained.

With just over two weeks to until national polling day, Prime Minister Theresa May was supposed to be spending the day in Tory heartland - in Somerset seats in idyllic south-west England. The welcome the Tory leader would have enjoyed might have been respite from her worst day on the campaign trail and potentially of her 10-month-old prime ministership.

But Tuesday would bring horror, visits to children's hospitals and sympathetic calls from world leaders, including US President Donald Trump and Australian Prime Minister Malcolm Turnbull.

At 10.33pm on Monday, a suicide bomber struck the Manchester Arena, targeting young fans of popstar Ariana Grande as her Dangerous Woman concert came to a close. Saffie Roussos, just eight years old, would be named by the headmaster of her primary school as one of the 22 victims.

May immediately suspended the campaign.

The former home secretary stayed up throughout the night overseeing the response and taking updates. At 4am she spoke to her opponent Jeremy Corbyn to agree to indefinitely halt the politicking.

Just before midday, she stood outside 10 Downing Street and gave one of her trademark tough but determined, heartfelt but commanding and calm, methodical addresses.

This was vintage May - the resolute stateswoman.

Just 12 hours earlier the political landscape she faced could not have been more different and - for a leader who has soared sky-high in the polls - discomfitting.

On Monday May was being derided as "weak and wobbly" a counter to her claim, repeated ad nauseam, of being "strong and stable." It followed another disastrous policy proposal, Tory backlash and subsequent backdown.

This time it was over what the British press dubbed the 'Dementia Tax' - a scheme unveiled in last Thursday's conservative manifesto that would allow the government to claim against the deceased estates of the elderly for the care they'd received in their homes.

The Tories' 20-point lead in some polls halved. Four days later May, was promising there would be a cap on the absolute limit that would have to be paid.

The Tory backlash and U-turn mirrored a similar episode in March over a budget proposal to raise national insurance costs for the self-employed - a proposal that contradicted the last Conservative manifesto.

May was hammered on both in her prime-time interview on the BBC with the veteran political commentator Andrew Neil - widely reported to be one of her worst performances. Her voice wavered and she was noticeably higher in pitch as Neil challenged her over her broken promises and issues of trust.

This was May under pressure.

But all of this will be swept aside and very likely forgotten as a result of the Manchester atrocity.

The campaign, with 16 days to go, is on hold "until further notice," Downing Street said. But even when it resumes, the tone will be different.

Domestic social care policies will go backstage, with the spotlight on national security, issues of cultural and national identity - which will play to Tory and Theresa May strengths.

Overwhelmingly, national unity will be paramount and there will be little complaint.

"Powerful statement from Theresa May, thank you.#WeWillNeverBeBroken," Jo Cox's husband, Brendan, tweeted as the prime minister wound up her 14-minute statement.

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